The bodies came through the night and through the morning, their faces black with blood that had pooled and darkened under the skin.

At midnight, under the light of nearly a thousand flares and squid boats strung with lines of high-powered lanterns, navy divers succeeded in entering the submerged Sewol ferry.

The first team broke a cabin window with a spiked hammer on one deck to retrieve the bodies of three students seen inside the day before. As another team opened one of the exit doors, three more bodies floated out, pushed by the current flowing through the ship's narrow passages.

A total of 18 bodies were brought out from inside the ship, bringing the number of dead to 58 and the number of those still missing to 244, the majority of them students from Danwon high school near Seoul. But there was more confusion over how many people were on board, with CCTV footage showing several lorries driving onto the ferry without tickets, possibly adding to problems in the cargo hold.

There were further questions over handling of the emergency as a transcript released of exchanges between the Sewol and Jindo Vessel Traffic Services Centre revealed indecision and miscommunication over whether to abandon ship.

Prosecutors investigating the disaster said some of the 20 surviving crew members had confessed they had not had any training on dealing with emergencies at sea. In other developments yesterday:

South Korean President Park Geun Hye says the captain and some crew members of the sunken ferry committed "unforgivable, murderous acts" in the disaster. Park said they "told the passengers to stay put but they themselves became the first to escape, after deserting the passengers". She said that "legally and ethically, this is an unimaginable act".

Prosecutors said they detained four crew members - two first mates, a second mate and a chief engineer - whom they suspect of failing to protect passengers. The captain and two crew members were formally arrested a day earlier.

On the wharf at Pangmok Harbour, Jindo, where the bodies were brought to shore, a small group of fathers huddled inside a temporary shelter.

"We are tired," said Jin Kwangyung, 53, whose daughter Yoonhwe is among the missing. "We have almost given up. When we see anything we get very angry."

At dawn, scuffles broke out on the wharf after a mix-up delayed a boat carrying three bodies from docking for almost two hours while parents waited to see if their children were on board.

Divers have described the task that faces them in extracting the bodies as monumental.

"This is the hardest situation I have ever seen," said Dae Sik Hwang, the head of South Korea's Maritime Rescue Operation, which is co-ordinating the civilian dive teams. "This is the worst place it could have happened in [South] Korea because of the current underwater. It is one of the most dangerous places in the world to dive."

Out at sea, 2m waves buffet the dinghies used by divers to reach the scene. The bows of the ferry now lie more than 15m beneath the water at high tide.

"There are no survivors," said Hwang.

At the current rate of progress, it could take two to three more weeks to retrieve all the victims. In a tent behind Hwang, a group of divers discuss the best points of entry to the ferry, parts of which lie at a depth of 43m. While there are 560 divers at the site, only six can enter at any one time.

The divers in Jindo said water rushing through the ship had pinned internal doors shut and the bodies trapped inside were becoming bloated, making them difficult to manoeuvre through the narrow passageways.

The Government has designated the site of the sinking, and the city of Ansan, the home of Danwon high school, as "special disaster zones" to free up money outside its annual budget for compensation to the parents and for the continuing salvage operation. But that has failed to assuage the anger of families.

When Jeong Hong Won, South Korea's Prime Minister, arrived at the scene, his car was quickly surrounded.

"Why did you dither over the rescue?" one shouted. "Can't you see the mess over who is leading the operation?" asked another. "Wake up! Bring my son back!" one screamed. "Get out of the car! Don't you have children?"

Battle for clarity over rescue plan

The transcript: South Korea's coastguard says about 30 minutes after the Sewol began tilting a crew member asked a marine traffic controller whether passengers would be rescued if they abandoned ship off South Korea's southern coast. That followed statements from the ship crew members that people on board could not move and it was "impossible to broadcast" instructions.

Jindo Vessel Traffic Services Centre official to crew: "[They should] go out and let the passengers wear lifejackets and put on more clothing".

Unidentified crew member: "If this ferry evacuates passengers, will you be able to rescue them?"

Official: "At least make them wear life rings and make them escape!"

Crew: "If this ferry evacuates passengers, will they be rescued right away?"

Official: "Don't let them go bare, at least make them wear life rings and make them escape. The rescue of human lives from the Sewol ferry ... the captain should make his own decision and evacuate them. We don't know the situation very well. The captain should make the final decision and decide whether you're going to evacuate passengers or not."

Crew: "I'm not talking about that. I asked if they evacuate now, can they be rescued right away?"

Official: Then said patrol boats would arrive in 10 minutes, though another civilian ship was already nearby and had told controllers that it would rescue anyone who went overboard.